Downlink control information (dci) design for low cost devices

ABSTRACT

Certain aspects of the present disclosure relate to techniques for reducing the decoding complexity for low cost devices (e.g., low cost UEs). One technique may include simplifying the PDCCH format. This may include generating a compact DCI format for transmitting DCI to a low cost device. The compact DCI format may correspond to at least one standard DCI format used by a regular UE and may comprise a reduced number of bits when compared to the standard DCI format. Another technique may include reducing the number of blind decodes. This technique may include selecting a set of resources for transmitting DCI from a limited set of decoding candidates, such that a receiving low cost device need only perform blind decodes for the limited set of decoding candidates.

The present Application for Patent claims priority to U.S. ProvisionalApplication No. 61/560,337, entitled “DOWNLINK CONTROL INFORMATION (DCI)DESIGN FOR LOW COST DEVICES,” filed Nov. 16, 2011, and assigned to theassignee hereof and hereby expressly incorporated by reference herein.

BACKGROUND

1. Field

Aspects of the present disclosure relate generally to wirelesscommunication systems, and more particularly, to Downlink ControlInformation (DCI) design for low cost devices.

2. Background

Wireless communication networks are widely deployed to provide variouscommunication services such as voice, video, packet data, messaging,broadcast, etc. These wireless networks may be multiple-access networkscapable of supporting multiple users by sharing the available networkresources. Examples of such multiple-access networks include CodeDivision Multiple Access (CDMA) networks, Time Division Multiple Access(TDMA) networks, Frequency Division Multiple Access (FDMA) networks,Orthogonal FDMA (OFDMA) networks, and Single-Carrier FDMA (SC-FDMA)networks.

A wireless communication network may include a number of base stationsthat can support communication for a number of user equipments (UEs). AUE may communicate with a base station via the downlink and uplink. Thedownlink (or forward link) refers to the communication link from thebase station to the UE, and the uplink (or reverse link) refers to thecommunication link from the UE to the base station.

SUMMARY

Certain aspects of the present disclosure provide a method for wirelesscommunications. The method generally includes generating a compactDownlink Control Information (DCI) format for transmitting DCI for usein at least one of uplink (UL) or downlink (DL) transmissions by a firstdevice of a first type, wherein the compact DCI format corresponds to atleast one standard DCI format used by a second device of a second typeand comprises a reduced number of bits when compared to the standard DCIformat, and transmitting the DCI according to the compact DCI format.

Certain aspects of the present disclosure provide an apparatus forwireless communications. The apparatus generally includes means forgenerating a compact Downlink Control Information (DCI) format fortransmitting DCI for use in at least one of uplink (UL) or downlink (DL)transmissions by a first device of a first type, wherein the compact DCIformat corresponds to at least one standard DCI format used by a seconddevice of a second type and comprises a reduced number of bits whencompared to the standard DCI format, and means for transmitting the DCIaccording to the compact DCI format.

Certain aspects of the present disclosure provide an apparatus forwireless communications. The apparatus generally includes at least oneprocessor and a memory coupled to the at least one processor. The atleast one processor is generally configured to generate a compactDownlink Control Information (DCI) format for transmitting DCI for usein at least one of uplink (UL) or downlink (DL) transmissions by a firstdevice of a first type, wherein the compact DCI format corresponds to atleast one standard DCI format used by a second device of a second typeand comprises a reduced number of bits when compared to the standard DCIformat, and transmit the DCI according to the compact DCI format.

Certain aspects of the present disclosure provide a computer programproduct for wireless communications. The computer program productgenerally includes a computer-readable medium comprising code forgenerating a compact Downlink Control Information (DCI) format fortransmitting DCI for use in at least one of uplink (UL) or downlink (DL)transmissions by a first device of a first type, wherein the compact DCIformat corresponds to at least one standard DCI format used by a seconddevice of a second type and comprises a reduced number of bits whencompared to the standard DCI format, and transmitting the DCI accordingto the compact DCI format.

Certain aspects of the present disclosure provide a method for wirelesscommunications. The method generally includes receiving Downlink ControlInformation (DCI) according to a compact DCI format for use in at leastone of uplink (UL) or downlink (DL) transmissions, wherein the compactDCI format corresponds to at least one standard DCI format used by asecond device of a second type and comprises a reduced number of bitswhen compared to the standard DCI format, and processing the receivedDCI.

Certain aspects of the present disclosure provide an apparatus forwireless communications means for receiving Downlink Control Information(DCI) according to a compact DCI format for use in at least one ofuplink (UL) or downlink (DL) transmissions, wherein the compact DCIformat corresponds to at least one standard DCI format used by a seconddevice of a second type and comprises a reduced number of bits whencompared to the standard DCI format, and means for processing thereceived DCI.

Certain aspects of the present disclosure provide an apparatus forwireless communications. The apparatus generally includes at least oneprocessor and a memory coupled to the at least one processor. The atleast one processor is generally configured to receive Downlink ControlInformation (DCI) according to a compact DCI format for use in at leastone of uplink (UL) or downlink (DL) transmissions, wherein the compactDCI format corresponds to at least one standard DCI format used by asecond device of a second type and comprises a reduced number of bitswhen compared to the standard DCI format, and process the received DCI.

Certain aspects of the present disclosure provide a computer programproduct for wireless communications. The computer program productgenerally includes a computer-readable medium comprising code forreceiving Downlink Control Information (DCI) according to a compact DCIformat for use in at least one of uplink (UL) or downlink (DL)transmissions, wherein the compact DCI format corresponds to at leastone standard DCI format used by a second device of a second type andcomprises a reduced number of bits when compared to the standard DCIformat, and processing the received DCI.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram conceptually illustrating an example of atelecommunications system.

FIG. 2 is a block diagram conceptually illustrating an example of a downlink frame structure in a telecommunications system.

FIG. 3 shows a block diagram conceptually illustrating an example of aNode B in communication with a user equipment device (UE) in a wirelesscommunications network in accordance with certain aspects of the presentdisclosure.

FIG. 4 illustrates an example comparison of legacy DCI format 1A andcorresponding compact DCI format, in accordance with certain aspects ofthe disclosure.

FIG. 5 illustrates an example comparison of legacy DCI format 0 andcorresponding compact DCI format, in accordance with certain aspects ofthe disclosure.

FIG. 6 illustrates example operations, which may be performed by a basestation (BS), for generating DCI in accordance with certain aspects ofthe disclosure.

FIG. 7 illustrates example operations, which may be performed by a userequipment (UE) (e.g., a low cost UE), for receiving and processing DCIin accordance with certain aspects of the disclosure.

DETAILED DESCRIPTION

The detailed description set forth below, in connection with theappended drawings, is intended as a description of variousconfigurations and is not intended to represent the only configurationsin which the concepts described herein may be practiced. The detaileddescription includes specific details for the purpose of providing athorough understanding of the various concepts. However, it will beapparent to those skilled in the art that these concepts may bepracticed without these specific details. In some instances, well-knownstructures and components are shown in block diagram form in order toavoid obscuring such concepts.

The techniques described herein may be used for various wirelesscommunication networks such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA andother networks. The terms “network” and “system” are often usedinterchangeably. A CDMA network may implement a radio technology such asUniversal Terrestrial Radio Access (UTRA), cdma2000, etc. UTRA includesWideband CDMA (WCDMA) and other variants of CDMA. cdma2000 coversIS-2000, IS-95 and IS-856 standards. A TDMA network may implement aradio technology such as Global System for Mobile Communications (GSM).An OFDMA network may implement a radio technology such as Evolved UTRA(E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16(WiMAX), IEEE 802.20, Flash-OFDMA, etc. UTRA and E-UTRA are part ofUniversal Mobile Telecommunication System (UMTS). 3GPP Long TermEvolution (LTE) and LTE-Advanced (LTE-A) are new releases of UMTS thatuse E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A and GSM are described indocuments from an organization named “3rd Generation PartnershipProject” (3GPP). cdma2000 and UMB are described in documents from anorganization named “3rd Generation Partnership Project 2” (3GPP2). Thetechniques described herein may be used for the wireless networks andradio technologies mentioned above as well as other wireless networksand radio technologies. For clarity, certain aspects of the techniquesare described below for LTE, and LTE terminology is used in much of thedescription below.

FIG. 1 shows a wireless communication network 100, which may be an LTEnetwork. The wireless network 100 may include a number of evolved NodeBs (eNodeBs) 110 and other network entities. An eNodeB may be a stationthat communicates with the UEs and may also be referred to as a basestation, an access point, etc. A Node B is another example of a stationthat communicates with the UEs.

Each eNodeB 110 may provide communication coverage for a particulargeographic area. In 3GPP, the term “cell” can refer to a coverage areaof an eNodeB and/or an eNodeB subsystem serving this coverage area,depending on the context in which the term is used.

An eNodeB may provide communication coverage for a macro cell, a picocell, a femto cell, and/or other types of cell. A macro cell may cover arelatively large geographic area (e.g., several kilometers in radius)and may allow unrestricted access by UEs with service subscription. Apico cell may cover a relatively small geographic area and may allowunrestricted access by UEs with service subscription. A femto cell maycover a relatively small geographic area (e.g., a home) and may allowrestricted access by UEs having association with the femto cell (e.g.,UEs in a Closed Subscriber Group (CSG), UEs for users in the home,etc.). An eNodeB for a macro cell may be referred to as a macro eNodeB.An eNodeB for a pico cell may be referred to as a pico eNodeB. An eNodeBfor a femto cell may be referred to as a femto eNodeB or a home eNodeB.In the example shown in FIG. 1, the eNodeBs 110 a, 110 b and 110 c maybe macro eNodeBs for the macro cells 102 a, 102 b and 102 c,respectively. The eNodeB 110 x may be a pico eNodeB for a pico cell 102x. The eNodeBs 110 y and 110 z may be femto eNodeBs for the femto cells102 y and 102 z, respectively. An eNodeB may support one or multiple(e.g., three) cells.

The wireless network 100 may also include relay stations. A relaystation is a station that receives a transmission of data and/or otherinformation from an upstream station (e.g., an eNodeB or a UE) and sendsa transmission of the data and/or other information to a downstreamstation (e.g., a UE or an eNodeB). A relay station may also be a UE thatrelays transmissions for other UEs. In the example shown in FIG. 1, arelay station 110 r may communicate with the eNodeB 110 a and a UE 120 rin order to facilitate communication between the eNodeB 110 a and the UE120 r. A relay station may also be referred to as a relay eNodeB, arelay, etc.

The wireless network 100 may be a heterogeneous network that includeseNodeBs of different types, e.g., macro eNodeBs, pico eNodeBs, femtoeNodeBs, relays, etc. These different types of eNodeBs may havedifferent transmit power levels, different coverage areas, and differentimpact on interference in the wireless network 100. For example, macroeNodeBs may have a high transmit power level (e.g., 20 Watts) whereaspico eNodeBs, femto eNodeBs and relays may have a lower transmit powerlevel (e.g., 1 Watt).

The wireless network 100 may support synchronous or asynchronousoperation. For synchronous operation, the eNodeBs may have similar frametiming, and transmissions from different eNodeBs may be approximatelyaligned in time. For asynchronous operation, the eNodeBs may havedifferent frame timing, and transmissions from different eNodeBs may notbe aligned in time. The techniques described herein may be used for bothsynchronous and asynchronous operation.

A network controller 130 may couple to a set of eNodeBs and providecoordination and control for these eNodeBs. The network controller 130may communicate with the eNodeBs 110 via a backhaul. The eNodeBs 110 mayalso communicate with one another, e.g., directly or indirectly viawireless or wireline backhaul.

The UEs 120 (e.g., 120 x, 120 y, etc.) may be dispersed throughout thewireless network 100, and each UE may be stationary or mobile. A UE mayalso be referred to as a terminal, a mobile station, a subscriber unit,a station, etc. A UE may be a cellular phone, a personal digitalassistant (PDA), a wireless modem, a wireless communication device, ahandheld device, a laptop computer, a cordless phone, a wireless localloop (WLL) station, a tablet, a netbook, a smart book, etc. A UE may beable to communicate with macro eNodeBs, pico eNodeBs, femto eNodeBs,relays, etc. In FIG. 1, a solid line with double arrows indicatesdesired transmissions between a UE and a serving eNodeB, which is aneNodeB designated to serve the UE on the downlink and/or uplink. Adashed line with double arrows indicates interfering transmissionsbetween a UE and an eNodeB.

LTE utilizes orthogonal frequency division multiplexing (OFDM) on thedownlink and single-carrier frequency division multiplexing (SC-FDM) onthe uplink. OFDM and SC-FDM partition the system bandwidth into multiple(K) orthogonal subcarriers, which are also commonly referred to astones, bins, etc. Each subcarrier may be modulated with data. Ingeneral, modulation symbols are sent in the frequency domain with OFDMand in the time domain with SC-FDM. The spacing between adjacentsubcarriers may be fixed, and the total number of subcarriers (K) may bedependent on the system bandwidth. For example, the spacing of thesubcarriers may be 15 kHz and the minimum resource allocation (called a‘resource block’) may be 12 subcarriers (or 180 kHz). Consequently, thenominal FFT size may be equal to 128, 256, 512, 1024 or 2048 for systembandwidth of 1.25, 2.5, 5, 10 or 20 megahertz (MHz), respectively. Thesystem bandwidth may also be partitioned into subbands. For example, asubband may cover 1.08 MHz (i.e., 6 resource blocks), and there may be1, 2, 4, 8 or 16 subbands for system bandwidth of 1.25, 2.5, 5, 10 or 20MHz, respectively.

FIG. 2 shows a down link frame structure used in LTE. The transmissiontimeline for the downlink may be partitioned into units of radio frames.Each radio frame may have a predetermined duration (e.g., 10milliseconds (ms)) and may be partitioned into 10 sub-frames withindices of 0 through 9. Each sub-frame may include two slots. Each radioframe may thus include 20 slots with indices of 0 through 19. Each slotmay include L symbol periods, e.g., 7 symbol periods for a normal cyclicprefix (as shown in FIG. 2) or 14 symbol periods for an extended cyclicprefix. The 2 L symbol periods in each sub-frame may be assigned indicesof 0 through 2 L−1. The available time frequency resources may bepartitioned into resource blocks. Each resource block may cover Nsubcarriers (e.g., 12 subcarriers) in one slot.

In LTE, an eNodeB may send a primary synchronization signal (PSS) and asecondary synchronization signal (SSS) for each cell in the eNodeB. Theprimary and secondary synchronization signals may be sent in symbolperiods 6 and 5, respectively, in each of sub-frames 0 and 5 of eachradio frame with the normal cyclic prefix, as shown in FIG. 2. Thesynchronization signals may be used by UEs for cell detection andacquisition. The eNodeB may send a Physical Broadcast Channel (PBCH) insymbol periods 0 to 3 in slot 1 of sub-frame 0. The PBCH may carrycertain system information.

The eNodeB may send a Physical Control Format Indicator Channel (PCFICH)in only a portion of the first symbol period of each sub-frame, althoughdepicted in the entire first symbol period in FIG. 2. The PCFICH mayconvey the number of symbol periods (M) used for control channels, whereM may be equal to 1, 2 or 3 and may change from sub-frame to sub-frame.M may also be equal to 4 for a small system bandwidth, e.g., with lessthan 10 resource blocks. In the example shown in FIG. 2, M=3. The eNodeBmay send a Physical HARQ Indicator Channel (PHICH) and a PhysicalDownlink Control Channel (PDCCH) in the first M symbol periods of eachsub-frame (M=3 in FIG. 2). The PHICH may carry information to supporthybrid automatic retransmission (HARQ). The PDCCH may carry informationon uplink and downlink resource allocation for UEs and power controlinformation for uplink channels. Although not shown in the first symbolperiod in FIG. 2, it is understood that the PDCCH and PHICH are alsoincluded in the first symbol period. Similarly, the PHICH and PDCCH arealso both in the second and third symbol periods, although not shownthat way in FIG. 2. The eNodeB may send a Physical Downlink SharedChannel (PDSCH) in the remaining symbol periods of each sub-frame. ThePDSCH may carry data for UEs scheduled for data transmission on thedownlink. The various signals and channels in LTE are described in 3GPPTS 36.211, entitled “Evolved Universal Terrestrial Radio Access(E-UTRA); Physical Channels and Modulation,” which is publiclyavailable.

The eNodeB may send the PSS, SSS and PBCH in the center 1.08 MHz of thesystem bandwidth used by the eNodeB. The eNodeB may send the PCFICH andPHICH across the entire system bandwidth in each symbol period in whichthese channels are sent. The eNodeB may send the PDCCH to groups of UEsin certain portions of the system bandwidth. The eNodeB may send thePDSCH to specific UEs in specific portions of the system bandwidth. TheeNodeB may send the PSS, SSS, PBCH, PCFICH and PHICH in a broadcastmanner to all UEs, may send the PDCCH in a unicast manner to specificUEs, and may also send the PDSCH in a unicast manner to specific UEs.

A number of resource elements may be available in each symbol period.Each resource element may cover one subcarrier in one symbol period andmay be used to send one modulation symbol, which may be a real orcomplex value. Resource elements not used for a reference signal in eachsymbol period may be arranged into resource element groups (REGs). EachREG may include four resource elements in one symbol period. The PCFICHmay occupy four REGs, which may be spaced approximately equally acrossfrequency, in symbol period 0. The PHICH may occupy three REGs, whichmay be spread across frequency, in one or more configurable symbolperiods. For example, the three REGs for the PHICH may all belong insymbol period 0 or may be spread in symbol periods 0, 1 and 2. The PDCCHmay occupy 9, 18, 32 or 64 REGs, which may be selected from theavailable REGs, in the first M symbol periods. Only certain combinationsof REGs may be allowed for the PDCCH.

A UE may know the specific REGs used for the PHICH and the PCFICH. TheUE may search different combinations of REGs for the PDCCH. The numberof combinations to search is typically less than the number of allowedcombinations for the PDCCH. An eNodeB may send the PDCCH to the UE inany of the combinations that the UE will search.

A UE may be within the coverage of multiple eNodeBs. One of theseeNodeBs may be selected to serve the UE. The serving eNodeB may beselected based on various criteria such as received power, path loss,signal-to-noise ratio (SNR), etc.

FIG. 3 shows a block diagram of a design of a base station or an eNB 110and a UE 120, which may be one of the base stations/eNBs and one of theUEs in FIG. 1. For a restricted association scenario, the eNB 110 may bemacro eNB 110 c in FIG. 1, and UE 120 may be UE 120 y. The eNB 110 mayalso be a base station of some other type. The eNB 110 may be equippedwith T antennas 334 a through 334 t, and the UE 120 may be equipped withR antennas 352 a through 352 r, where in general T≧1 and R≧1.

At the eNB 110, a transmit processor 320 may receive data from a datasource 312 and control information from a controller/processor 340. Thecontrol information may be for the PBCH, PCFICH, PHICH, PDCCH, etc. Thedata may be for the PDSCH, etc. The transmit processor 320 may process(e.g., encode and symbol map) the data and control information to obtaindata symbols and control symbols, respectively. The transmit processor320 may also generate reference symbols, e.g., for the PSS, SSS, andcell-specific reference signal. A transmit (TX) multiple-inputmultiple-output (MIMO) processor 330 may perform spatial processing(e.g., precoding) on the data symbols, the control symbols, and/or thereference symbols, if applicable, and may provide T output symbolstreams to T modulators (MODs) 332 a through 332 t. Each modulator 332may process a respective output symbol stream (e.g., for OFDM, etc.) toobtain an output sample stream. Each modulator 332 may further process(e.g., convert to analog, amplify, filter, and upconvert) the outputsample stream to obtain a downlink signal. T downlink signals frommodulators 332 a through 332 t may be transmitted via T antennas 334 athrough 334 t, respectively.

At the UE 120, antennas 352 a through 352 r may receive the downlinksignals from the eNB 110 and may provide received signals todemodulators (DEMODs) 354 a through 354 r, respectively. Eachdemodulator 354 may condition (e.g., filter, amplify, downconvert, anddigitize) a respective received signal to obtain input samples. Eachdemodulator 354 may further process the input samples (e.g., for OFDM,etc.) to obtain received symbols. A MIMO detector 356 may obtainreceived symbols from all R demodulators 354 a through 354 r, performMIMO detection on the received symbols, if applicable, and providedetected symbols. A receive processor 358 may process (e.g., demodulate,deinterleave, and decode) the detected symbols, provide decoded data forthe UE 120 to a data sink 360, and provide decoded control informationto a controller/processor 380.

On the uplink, at the UE 120, a transmit processor 364 may receive andprocess data (e.g., for the PUSCH) from a data source 362 and controlinformation (e.g., for the PUCCH) from the controller/processor 380. Thetransmit processor 364 may also generate reference symbols for areference signal. The symbols from the transmit processor 364 may beprecoded by a TX MIMO processor 366 if applicable, further processed bymodulators 354a through 354 r (e.g., for SC-FDM, etc.), and transmittedto the eNB 110. At the eNB 110, the uplink signals from the UE 120 maybe received by antennas 334, processed by demodulators 332, detected bya MIMO detector 336 if applicable, and further processed by a receiveprocessor 338 to obtain decoded data and control information sent by theUE 120. The receive processor 338 may provide the decoded data to a datasink 339 and the decoded control information to the controller/processor340.

The controllers/processors 340, 380 may direct the operation at the eNB110 and the UE 120, respectively. The controller/processor 380 and/orother processors and modules at the UE 120 may perform or directoperations for blocks 800 in FIG. 8, operations for blocks 1000 in FIG.10, operations for blocks 1100 in FIG. 11, and/or other processes forthe techniques described herein. The memories 342 and 382 may store dataand program codes for base station 110 and UE 120, respectively. Ascheduler 344 may schedule UEs for data transmission on the downlinkand/or uplink.

In LTE, cell identities range from 0 to 503. Synchronization signals aretransmitted in the center 62 resource elements (REs) around the DC toneto help detect cells. The synchronization signals comprise two parts: aPrimary Synchronization Signal (PSS) and a Secondary SynchronizationSignal (SSS).

In one configuration, the base station 110 includes means for generatinga compact Downlink Control Information (DCI) format for transmitting DCIfor use in at least one of uplink (UL) or downlink (DL) transmissions bya low cost UE, wherein the compact DCI format corresponds to at leastone standard DCI format used by a regular UE and comprises a reducednumber of bits when compared to the standard DCI format, and means fortransmitting the DCI according to the compact DCI format. In one aspect,the aforementioned means may include controller/processor 340, thememory 342, the transmit processor 320, the modulators 332, and theantennas 334, or a combination thereof, configured to perform thefunctions recited by the aforementioned means. In another aspect, anaforementioned means may include a module or any apparatus configured toperform the functions recited by the aforementioned means.

In one configuration, the UE 120 (e.g., low cost UE) includes means forreceiving the DCI for at least one of uplink (UL) or downlink (DL)transmissions, transmitted according to the compact DCI format, whereinthe DCI comprises a reduced number of bits when compared to a standardDCI format, and means for processing the DCI. In one aspect, theaforementioned means may include the controller/processor 380, thememory 382, the receive processor 358, the MIMO detector 356, thedemodulators 354, and the antennas 352, or a combination thereof,configured to perform the functions recited by the aforementioned means.In another aspect, an aforementioned means may include a module or anyapparatus configured to perform the functions recited by theaforementioned means.

Example DCI Design for Low Cost Devices

In LTE Rel-8/9/10, each PDCCH follows downlink control information (DCI)format. Downlink (DL) grant DCI formats may include DCI formats 1, 1A,1B, 1D, 2, 2A, 2B and 2C. Uplink (UL) DCI grant DCI formats may includeDCI formats 0 and 4. Broadcast/multicast DCI formats may include DCIformats 1C, 3 and 3A.

In certain aspects, each DCI format contains a 16-bit Cyclic RedundancyCheck (CRC), which is masked by an identifier (ID) (e.g. UE-specific IDor a broadcast/multicast ID). In an aspect, the size of the DCI maydepend on the system bandwidth, system type (e.g. Frequency divisionDuplex (FDD) or Time Division Duplex (TDD)), number of common referencesignal (CRS) antenna ports, DCI format, carrier aggregation or not, etc.The size of the DCI is typically tens of bits (e.g. 30-70 bits)including CRC. In addition, a UE may need to perform blind decodes todetermine whether there is one or more PDCCHs addressed to it or not. Inan aspect, the number of blind decodes may be up to 44 in LTE Rel-8 and9, and up to 60 in LTE Rel-10, when UL MIMO is configured.

In Rel-11 and beyond, low cost devices (e.g., low cost UE) may besupported. Generally, low cost devices are meant for machine typecommunications, and cost lower and have reduced processing capabilitieswhen compared to regular UEs. In certain aspects, these low cost devicesmay operate in small system bandwidth cells, and may be expected to haveless processing power. In certain aspects, scheduling flexibility,channel exploitation (e.g., MCS), resource allocation flexibility, etc.,are relatively less important for low cost devices than regular UEs.

In certain aspects, maintaining the same PDCCH design as regular UEs forlow cost UEs may result in a decoding complexity, which the low costdevice may not be capable of handling. Certain aspects of the presentdisclosure discuss techniques for reducing the decoding complexity forlow cost devices (e.g., low cost UEs). One technique may includesimplifying the PDCCH format to save the low cost device from largeamount of processing. This may be accomplished by generating a compactDCI format for transmitting DCI to a low cost device. The compact DCIformat may correspond to at least one standard DCI format used by aregular UE and may comprise a reduced number of bits when compared tothe standard DCI format. Another technique may include reducing thenumber of blind decodes (discussed above) in order to reduce the amountof processing by the low cost device. This technique may includeselecting a set of resources for transmitting DCI from a limited set ofdecoding candidates, such that a receiving low cost device need onlyperform blind decodes for the limited set of decoding candidates.

As noted above, in accordance with the first technique, the size of aDCI format may be reduced, for example, to achieve better PDCCH overheadefficiency, while having limited impact on scheduling, resourceallocation, channel utilization, flexibility and the like.

In certain aspects, a DCI design for low cost devices may include DCIdesign with limited resource allocation. For example, for a small systembandwidth (e.g., 6 resource blocks RBs) monitored by a low cost UEs, theDCI may allocate resources for one user at a time. In this case noresource allocation information field may be needed in the DCI, andthus, the DCI may be generated without bits allocated for the resourceallocation information.

In an alternative aspect, the DCI may be generated with limited set ofresource allocation possibilities. For example, considering a 6 RBsystem, and assuming that 4 RBs are available for data and 2 other RBsare available for control signalling, only 3 possible resourceallocations may be allowed, for example, all 4 RBs, the top 2 RBs, andthe bottom 2 RBs. This would require only 2 bits for resource allocationand may thus lead to a saving of 2 bits, compared to fully flexibleresource allocation in a regular DCI format.

In certain aspects, a DCI design for low cost devices may include DCIwith limited modulation and coding schemes (MCS). For instance, onlyQPSK, along with a limited set of possible coding rates (hence a limitedset of transport block sizes) may be allowed. For example, 4possibilities may need 2 bits in the DCI design, which may lead to asaving of 3 bits from the current LTE design.

In certain aspects, a DCI design for low cost devices may include DCIwith limited Hybrid Automatic Repeat Request (HARQ) processes. In anaspect, a limited set of H-ARQ processes may be allowed. For example,only one H-ARQ process may be allowed requiring no HARQ informationfield (e.g., for indicating a HARQ process) in the DCI. This may lead toa saving of 3 bits in frequency division duplex (FDD) and 4 bits in timedivision duplex (TDD).

In LTE Rel-8/9/10, DCI formats 1A and 0 have the same size, and one bitis used in the DCI to differentiate between the two formats. In certainaspects, this bit may be removed (e.g., for overhead efficiency) if theformats 1A and 0 are required to have different sizes. Thus, a DCIdesign for low cost devices may include DCI with no 1-bit flagdifferentiating DCI formats 1A and 0.

In certain aspects, a DCI design for low cost devices may include DCIdesign with reduced CRC length. For instance, 8-bit CRC (instead of theregular 16-bit CRC) may be used, as in the aperiodic channel qualityindicator (CQI) case in LTE. Alternatively, the same 16-bit CRCgenerator polynomial as in LTE may be used, but after applying sometruncation. For example, after the 16-bit CRC is generated, it may betruncated to K<16 bits. The truncated CRC may be appended to thetransmit information bits and further masked by the K LSB bits of theRadio Network Temporary Identifier (RNTI).

In certain aspects, a DCI design for low cost devices may include DCIwithout bits allocated for incremental redundancy. This may includealways assuming redundancy version (RV)=0, which may lead to a saving of2 bits.

In certain aspects, a DCI design for low cost devices may include DCIwithout bits allocated for aperiodic sounding reference signal (SRS)request. This may lead to a saving of one bit.

In certain aspects, a DCI design for low cost devices may include DCIwith reduced bit-width for transmitter power control TPC. In an aspect,instead of 2-bit TPC commands, 1-bit may be used, which may besufficient for low cost devices.

In certain aspects, a DCI design for low cost devices may include DCIwith reduced cyclic shift bit-width for Demodulation Reference Signal(DM-RS). In certain aspects, instead of 3 bits, 1-bit may be used toindicate two values.

In certain aspects, a DCI design for low cost devices may include DCIwithout a bit allocated for multi-cluster flag. This may lead to asaving of 1 bit.

In certain aspects, the aperiodic CSI may be kept only if needed, forexample if periodic CSI is not supported. In an aspect, in certain casesonly periodic CSI may be supported and the 1-bit aperiodic CSI may beremoved. Thus, a DCI design for low cost devices may include DCI withoutthe one bit allocated for aperiodic CSI. In an aspect, a low cost UE maydetermine whether periodic CSI is supported. The low cost UE may keepaperiodic CSI if periodic CSI is not supported, and remove aperiodic CSIif periodic CSI is supported.

In certain aspects, the localized/distributed virtual resource block(VRB) assignment flag may be removed. Thus, a DCI design for low costdevices may include DCI without one bit allocated for thelocalized/distributed VRB assignment flag.

In certain aspects, low cost UEs may be always required to hop or neverhop. Thus, a DCI design for the low cost devices may include DCI withoutone bit allocated for the frequency hopping flag (typically used toindicate hop or no hop).

In certain aspects, the Downlink Assignment Index (DAI) and ULassignment index (TDD) may be removed. In an aspect, this may beaccomplished by ensuring that there is always a one-to-one DL subframeto UL subframe mapping (e.g., for H-ARQ operation) for each UE, suchthat the need for DAI (e.g., due to multiple DL to one UL mapping) or ULassignment index (e.g., due to one DL to multiple UL mapping) isremoved. Thus, a DCI design for low cost devices may include DCI withouta bit allocated for DAI and UL assignment index.

In certain aspects, for different UEs, the mapping for DL subframe andUL subframe may be different for better load balancing. For example, fora UE 1, DL subframe x may be mapped to UL subframe y, and for UE 2, DLsubframe z may be mapped to UL subframe y. Thus, UL subframe y maps todifferent DL subframes (x and z) for the two UEs. In an aspect, the DLsubframe to UL subframe mapping may be indicated to the low costdevice(s) via Radio Resource Control (RRC) signaling.

FIG. 4 illustrates an example comparison 400 of legacy DCI format 1A andcorresponding compact DCI format, in accordance with certain aspects ofthe disclosure. Column 402 lists the fields for the DCI format 1A.Column 404 lists bit-widths for each field of legacy DCI format 1A andcolumn 408 lists bit-widths for each field of the compact DCI design forDCI format 1A, compacted using the techniques discussed above. Column410 discusses the specific technique used for each field 402 forreducing the number of bits in the compact DCI design.

Row 420 shows a total number of bits required for DCI according tolegacy DCI format 1A and the compact DCI format 1A. As shown in FIG. 4,DCI according to the legacy DCI format 1A requires 37 bits. However, DCIaccording to the compacted DCI format 1A, by employing techniquesdiscussed above, requires only 18 bits, which is a saving of more than50% of PDCCH overhead.

FIG. 5 illustrates an example comparison 500 of legacy DCI format 0 andcorresponding compact DCI format, in accordance with certain aspects ofthe disclosure. Column 502 lists the fields for the DCI format 0. Column504 lists bit-widths for each field of the legacy DCI format 0 andcolumn 508 lists bit-widths for each field of the compact DCI design forDCI format 0, compacted using the techniques discussed above. Column 510discusses the specific technique used for each field 502 for reducingthe number of bits in the compact DCI design.

Row 520 shows a total number of bits required for DCI according to thelegacy DCI format 0 and the compact DCI format 0. As shown in FIG. 5,the DCI according to legacy format 0 requires 37 bits. However, DCIaccording to the compacted format 0, by employing techniques discussedabove, requires only 19 bits, which is a saving of close to 50% of PDCCHoverhead.

FIG. 6 illustrates example operations 600, which may be performed by abase station (BS), for generating DCI in accordance with certain aspectsof the disclosure. Operations 600 may begin, at 602, by generating acompact DCI format for transmitting DCI for use in at least one of UL orDL transmissions by a first device of a first type, wherein the compactDCI format corresponds to at least one standard DCI format used by asecond device of a second type and comprises a reduced number of bitswhen compared to the standard DCI format. At 604, the BS may transmitthe DCI according to the compact DCI format. In an aspect, the device ofthe first type may include a low cost device (e.g., low cost UE) and adevice of a second type may include a regular UE. Further, as notedabove, the low cost UE may comprise reduced processing capability whencompared to the regular UE. In an aspect the BS may include eNB 110.

FIG. 7 illustrates example operations 700, which may be performed by auser equipment (UE) (e.g., a low cost UE), for receiving and processingDCI in accordance with certain aspects of the disclosure. Operations 700may begin, at 702, receiving DCI according to a compact DCI format foruse in at least one of UL or DL transmissions, wherein the compact DCIformat corresponds to at least one standard DCI format used by a seconddevice of a second type, and comprises a reduced number of bits whencompared to the standard DCI format. At 704, the UE may process thereceived DCI. In an aspect, the device of the first type may include alow cost device (e.g., low cost UE) and a device of a second type mayinclude a regular UE. Further, as noted above, the low cost UE maycomprise reduced processing capability when compared to the regular UE.In an aspect the UE may include UE 120.

In certain aspects, as noted above, another technique for reducingdecoding complexity at a low cost UE may include reducing the number ofblind PDCCH decodes in order to reduce the amount of processing by thelow cost device. As noted above, this technique may include selecting aset of resources for transmitting DCI from a limited set of decodingcandidates, such that a receiving low cost device need only performblind decodes for the limited set of decoding candidates

In an aspect, in addition to lesser decoding complexity, the number ofblind decodes may be reduced for less power consumption, and/or forpotentially lesser PDCCH payload size. In an aspect, the number of blindPDCCH decodes may be significantly reduced. For example, for 6 RBs, evenwith good channel conditions, the number of PDCCHs may be limited to,for e.g., four decoding candidates, if MU-MIMO is adopted for PDSCH andthere are 2 RBs for PDCCH. The four decoding candidates may include 2RBs-port 7, 2 RBs-port 8, 1 RB-port 7, and 1 RB-port 7. In this case,the number of blind decodes is 1/11^(th) of the original 44 blinddecodes. In an aspect, the lesser number of blind decodes may alsoenable a shorter CRC length.

Those of skill in the art would understand that information and signalsmay be represented using any of a variety of different technologies andtechniques. For example, data, instructions, commands, information,signals, bits, symbols, and chips that may be referenced throughout theabove description may be represented by voltages, currents,electromagnetic waves, magnetic fields or particles, optical fields orparticles, or any combination thereof.

Those of skill would further appreciate that the various illustrativelogical blocks, modules, circuits, and algorithm steps described inconnection with the disclosure herein may be implemented as electronichardware, computer software, or combinations of both. To clearlyillustrate this interchangeability of hardware and software, variousillustrative components, blocks, modules, circuits, and steps have beendescribed above generally in terms of their functionality. Whether suchfunctionality is implemented as hardware or software depends upon theparticular application and design constraints imposed on the overallsystem. Skilled artisans may implement the described functionality invarying ways for each particular application, but such implementationdecisions should not be interpreted as causing a departure from thescope of the present disclosure.

The various illustrative logical blocks, modules, and circuits describedin connection with the disclosure herein may be implemented or performedwith a general-purpose processor, a digital signal processor (DSP), anapplication specific integrated circuit (ASIC), a field programmablegate array (FPGA) or other programmable logic device, discrete gate ortransistor logic, discrete hardware components, or any combinationthereof designed to perform the functions described herein. Ageneral-purpose processor may be a microprocessor, but in thealternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

The steps of a method or algorithm described in connection with thedisclosure herein may be embodied directly in hardware, in a softwaremodule executed by a processor, or in a combination thereof. A softwaremodule may reside in RAM memory, flash memory, ROM memory, EPROM memory,EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or anyother form of storage medium known in the art. An exemplary storagemedium is coupled to the processor such that the processor can readinformation from, and write information to, the storage medium. In thealternative, the storage medium may be integral to the processor. Theprocessor and the storage medium may reside in an ASIC. The ASIC mayreside in a user terminal In the alternative, the processor and thestorage medium may reside as discrete components in a user terminal.

In one or more exemplary designs, the functions described may beimplemented in hardware, software/firmware, or various combinationsthereof. If implemented in software, the functions may be stored on ortransmitted over as one or more instructions or code on acomputer-readable medium. Computer-readable media includes both computerstorage media and communication media including any medium thatfacilitates transfer of a computer program from one place to another. Astorage media may be any available media that can be accessed by ageneral purpose or special purpose computer. By way of example, and notlimitation, such computer-readable media can comprise RAM, ROM, EEPROM,CD-ROM or other optical disk storage, magnetic disk storage or othermagnetic storage devices, or any other medium that can be used to carryor store desired program code means in the form of instructions or datastructures and that can be accessed by a general-purpose orspecial-purpose computer, or a general-purpose or special-purposeprocessor. Also, any connection is properly termed a computer-readablemedium. For example, if the software is transmitted from a website,server, or other remote source using a coaxial cable, fiber optic cable,twisted pair, digital subscriber line (DSL), or wireless technologiessuch as infrared, radio, and microwave, then the coaxial cable, fiberoptic cable, twisted pair, DSL, or wireless technologies such asinfrared, radio, and microwave are included in the definition of medium.Disk and disc, as used herein, includes compact disc (CD), laser disc,optical disc, digital versatile disc (DVD), floppy disk and Blu-ray discwhere disks usually reproduce data magnetically, while discs reproducedata optically with lasers. Combinations of the above should also beincluded within the scope of computer-readable media.

The previous description of the disclosure is provided to enable anyperson skilled in the art to make or use the disclosure. Variousmodifications to the disclosure will be readily apparent to thoseskilled in the art, and the generic principles defined herein may beapplied to other variations without departing from the spirit or scopeof the disclosure. Thus, the disclosure is not intended to be limited tothe examples and designs described herein but is to be accorded thewidest scope consistent with the principles and novel features disclosedherein.

What is claimed is:
 1. A method for wireless communications, comprising:generating a compact Downlink Control Information (DCI) format fortransmitting DCI for use in at least one of uplink (UL) or downlink (DL)transmissions by a first device of a first type, wherein the compact DCIformat corresponds to at least one standard DCI format used by a seconddevice of a second type and comprises a reduced number of bits whencompared to the standard DCI format; and transmitting the DCI accordingto the compact DCI format.
 2. The method of claim 1, wherein a device ofthe first type comprises reduced processing capability when compared toa device of the second type.
 3. The method of claim 1, wherein the firstdevice comprises a low cost User Equipment (UE).
 4. The method of claim1, wherein generating the DCI comprises: generating the DCI without bitsallocated for resource allocation information, wherein the DCI allocatesresources for one user at a time.
 5. The method of claim 1, whereingenerating the DCI comprises: generating the DCI for a limited set ofresource allocation possibilities.
 6. The method of claim 1, whereingenerating the DCI comprises: generating the DCI for a limitedmodulation and coding scheme (MCS).
 7. The method of claim 6, whereinthe limited MCS comprises Quadrature Phase Shift Keying (QPSK) only witha limited set of possible coding rates.
 8. The method of claim 1,wherein generating the DCI comprises: generating the DCI for a limitedset of Hybrid Automatic Repeat Request (HARQ) processes.
 9. The methodof claim 8, wherein the DCI lacks an indication of a HARQ process. 10.The method of claim 1, wherein generating the DCI comprises: generatingthe DCI without a bit allocated for differentiating between DCI formats1A and 0, wherein the DCI formats 1A and 0 have different sizes.
 11. Themethod of claim 1, wherein generating the DCI comprises: generating areduced length Cyclic Redundancy Check (CRC) for the DCI.
 12. The methodof claim 11, wherein generating the reduced length CRC comprises:generating a CRC of a first length and truncating the CRC of the firstlength to generate the reduced length CRC.
 13. The method of claim 1,wherein generating the DCI comprises: generating the DCI without bitsallocated for Redundancy Version (RV).
 14. The method of claim 1,wherein generating the DCI comprises: generating the DCI without bitsallocated for Sounding Reference Signal (SRS) request.
 15. The method ofclaim 1, wherein generating the DCI comprises: generating the DCI withreduced bit-width for Transmitter Power Control (TPC).
 16. The method ofclaim 1, wherein generating the DCI comprises: generating the DCI withreduced bit-width for Demodulation Reference Signal (DM-RS).
 17. Themethod of claim 1, wherein generating the DCI comprises: generating theDCI without a bit allocated for multi-cluster flag.
 18. The method ofclaim 1, wherein generating the DCI comprises: generating the DCIwithout a bit allocated for Virtual Resource Block assignment.
 19. Themethod of claim 1, further comprising determining whether periodicchannel state information (CSI) is supported; keeping aperiodic CSI ifperiodic CSI is not supported; and removing aperiodic CSI if periodicCSI is supported.
 20. The method of claim 1, wherein generating the DCIcomprises: generating the DCI without a bit allocated for frequencyhopping flag.
 21. The method of claim 1, wherein generating the DCIcomprises: generating the DCI without a bit allocated for DownlinkAssignment Index (DAI) and UL assignment index, wherein a one to onemapping is maintained between DL subframe and UL subframe for each UE.22. The method of claim 1, further comprising: selecting a set ofresources for transmitting the DCI from a limited set of decodingcandidates; and transmitting the DCI using the selected set ofresources, such that a receiving UE need only perform blind decodes forthe limited set of decoding candidates.
 23. An apparatus for wirelesscommunications, comprising: means for generating a compact DownlinkControl Information (DCI) format for transmitting DCI for use in atleast one of uplink (UL) or downlink (DL) transmissions by a firstdevice of a first type, wherein the compact DCI format corresponds to atleast one standard DCI format used by a second device of a second typeand comprises a reduced number of bits when compared to the standard DCIformat; and means for transmitting the DCI according to the compact DCIformat.
 24. The apparatus of claim 23, wherein a device of the firsttype comprises reduced processing capability when compared to a deviceof the second type.
 25. The apparatus of claim 23, wherein the firstdevice comprises a low cost User Equipment (UE).
 26. The apparatus ofclaim 23, further comprising: means for selecting a set of resources fortransmitting the DCI from a limited set of decoding candidates; andmeans for transmitting the DCI using the selected set of resources, suchthat a receiving UE need only perform blind decodes for the limited setof decoding candidates.
 27. An apparatus for wireless communications,comprising: at least one processor configured to: generate a compactDownlink Control Information (DCI) format for transmitting DCI for usein at least one of uplink (UL) or downlink (DL) transmissions by a firstdevice of a first type, wherein the compact DCI format corresponds to atleast one standard DCI format used by a second device of a second typeand comprises a reduced number of bits when compared to the standard DCIformat; and transmit the DCI according to the compact DCI format, amemory coupled to the at least one processor.
 28. A computer programproduct for wireless communications, comprising: a computer-readablemedium comprising code for: generating a compact Downlink ControlInformation (DCI) format for transmitting DCI for use in at least one ofuplink (UL) or downlink (DL) transmissions by a first device of a firsttype, wherein the compact DCI format corresponds to at least onestandard DCI format used by a second device of a second type andcomprises a reduced number of bits when compared to the standard DCIformat; and transmitting the DCI according to the compact DCI format.29. A method for wireless communications by a first device of a firsttype, comprising: receiving Downlink Control Information (DCI) accordingto a compact DCI format for use in at least one of uplink (UL) ordownlink (DL) transmissions, wherein the compact DCI format correspondsto at least one standard DCI format used by a second device of a secondtype and comprises a reduced number of bits when compared to thestandard DCI format; and processing the received DCI.
 30. The method ofclaim 29, wherein a device of the first type comprises reducedprocessing capability when compared to a device of the second type. 31.The method of claim 29, wherein the first device comprises a low costUser Equipment (UE).
 32. The method of claim 29, wherein the DCIcomprises: DCI without bits allocated for resource allocationinformation, wherein the DCI allocates resources for one user at a time.33. The method of claim 29, wherein the DCI comprises: DCI for a limitedset of resource allocation possibilities.
 34. The method of claim 29,wherein DCI comprises: DCI for a limited modulation and coding scheme(MCS).
 35. The method of claim 34, wherein the limited MCS comprisesQuadrature Phase Shift Keying (QPSK) only with a limited set of possiblecoding rates.
 36. The method of claim 29, wherein the DCI comprises: DCIfor a limited set of Hybrid Automatic Repeat Request (HARQ) processes.37. The method of claim 36, wherein the DCI lacks an indication of aHARQ process.
 38. The method of claim 29, wherein the DCI comprises: DCIwithout a bit allocated for differentiating between DCI formats 1A and0, wherein the DCI formats 1A and 0 have different sizes.
 39. The methodof claim 29, wherein the DCI comprises: a reduced length CyclicRedundancy Check (CRC) for the DCI.
 40. The method of claim 39, whereinthe reduced length CRC comprises: a CRC generated by generating a CRC ofa first length and truncating the CRC of the first length to generatethe reduced length CRC.
 41. The method of claim 29, wherein the DCIcomprises: DCI without bits allocated for Redundancy Version (RV). 42.The method of claim 29, wherein the DCI comprises: DCI without bitsallocated for Sounding Reference Signal (SRS) request.
 43. The method ofclaim 29, wherein the DCI comprises: DCI with reduced bit-width forTransmitter Power Control (TPC).
 44. The method of claim 29, wherein theDCI comprises: DCI with reduced bit-width for Demodulation ReferenceSignal (DM-RS).
 45. The method of claim 29, wherein the DCI comprises:DCI without a bit allocated for multi-cluster flag.
 46. The method ofclaim 29, wherein the DCI comprises: DCI with aperiodic channel stateinformation (CSI) if periodic CSI is not supported; and DCI withoutaperiodic CSI if periodic CSI is supported.
 47. The method of claim 29,wherein the DCI comprises: DCI without a bit allocated for VirtualResource Block assignment.
 48. The method of claim 29, wherein the DCIcomprises: DCI without a bit allocated for frequency hopping flag. 49.The method of claim 29, wherein the DCI comprises: DCI without a bitallocated for Downlink Assignment Index (DAI) and UL assignment index,wherein a one to one mapping is maintained between DL subframe and ULsubframe for each UE.
 50. The method of claim 29, wherein: the DCI istransmitted using a set of resources selected from a limited set ofdecoding candidates; and the method comprises performing blind decodesfor the limited set of decoding candidates to detect a PDCCH containingthe DCI.
 51. An apparatus for wireless communications by a first deviceof a first type, comprising: means for receiving Downlink ControlInformation (DCI) according to a compact DCI format for use in at leastone of uplink (UL) or downlink (DL) transmissions, wherein the compactDCI format corresponds to at least one standard DCI format used by asecond device of a second type and comprises a reduced number of bitswhen compared to the standard DCI format; and means for processing thereceived DCI.
 52. The apparatus of claim 51, wherein a device of thefirst type comprises reduced processing capability when compared to adevice of the second type.
 53. The apparatus of claim 51, wherein thefirst device comprises a low cost User Equipment (UE).
 54. The apparatusof claim 51, wherein: the DCI is transmitted using a set of resourcesselected from a limited set of decoding candidates; and the apparatuscomprises means for performing blind decodes for the limited set ofdecoding candidates to detect a PDCCH containing the DCI.
 55. Anapparatus for wireless communications by a first device of a first type,comprising: at least one processor configured to: receive DownlinkControl Information (DCI) according to a compact DCI format for use inat least one of uplink (UL) or downlink (DL) transmissions, wherein thecompact DCI format corresponds to at least one standard DCI format usedby a second device of a second type and comprises a reduced number ofbits when compared to the standard DCI format; and process the receivedDCI, and a memory coupled to the at least one processor.
 56. A computerprogram product for wireless communications by a first device of a firsttype, comprising: a computer-readable medium comprising code for:receiving Downlink Control Information (DCI) according to a compact DCIformat for use in at least one of uplink (UL) or downlink (DL)transmissions, wherein the compact DCI format corresponds to at leastone standard DCI format used by a second device of a second type andcomprises a reduced number of bits when compared to the standard DCIformat; and processing the received DCI. P&S Ref. No.: 120537US